documentation branch as a mirror of nginx/documentation

Author: eepifanova

.github/workflows/update_from_nginx_documentation.yml

@@ -21,5 +21,5 @@ jobs:
         git clone https://github.com/nginx/documentation.git
         cd documentation
         git remote add private [email protected]:${{ github.repository }}.git
-        git checkout -b public
-        git push private public
+        git checkout -b documentation
+        git push private documentation